Pneumatic valve



Dec. 31, 1935. OMSTED 2,026,056

PNEUMAT I C VALVE Filed June 50, 1950 Patented Dec. 31, 1935 NETED zczaose PNEUMATIC VALVE Kaare Omsted, San Jose, Calif., assignor to Food Machinery Corporation, San Jose, C'alif., a corporation of Delaware This invention relates to valves and operating mechanisms therefor, and has special utility when used in connection with devices for introducing charges of liquid or semi-liquid material into containers, although its use is by no means limited thereto.

Such devices ordinarily include a rotating hopper constituting a liquid reservoir having valvecontrolled outlets through which the liquid may pass at proper times to the containers which are to be filled. As the liquid is thus discharged from the hopper, some means must be provided for replenishment at approximately the same rate as the discharge. To this end a supply pipe is arranged to discharge into the hopper and is provided with a float-controlled valve which operates to allow the discharge of liquid into the hopper according to the level therein. It is with the construction of this valve and the operating mechanism therefor that my invention is concerned.

Heretofore, such valves have commonly been of the ordinary gate or puppet type and have been mechanically operated by a float resting upon the surface of the liquid in the hopper.

The results of such construction are highly unsatisfactory for many reasons. One of the chief difliculties is that the level of liquid in the hop per cannot be maintained constant but fluctuates between wide limits, causing a corresponding variation of pressure upon the discharge valves, with the result that the containers are not uniformly filled. The reason the level cannot be more closely regulated is that in order that the float may develop sufiicient energy to operate the supply valve, the consequent structural limitations make it necessary that the float move over a substantial distance while the valve moves a relatively short distance.

Another difiiculty arises when the apparatus is being used to charge containers with highly viscous liquids or semi-liquids. In such cases, the resistance of the liquid causes an undesirable sluggish movement of the valve, and since such liquids frequently have a tendency to become gummy or even solidified when quiescent operation of the valve may be prevented altogether. Moreover, it is almost impossible to prevent the liquid from seeping in around the valve stem where it causes the stem to stick, thus making it necessary to dis-assemble the valve for cleaning.

Similar difficulties are encountered when liquids containing sugar are being filled, since the sugar crystallizes and the crystals form around the valve and the valve stem and not only cause frequent sticking of the valve, but also reduce the area of the supply pipe.

Another cause of frequent annoyance develops when containers are being charged with liquids containing more or less acid, such as fruit juices and the like. Here again, the operation of the valve may be interfered with due to corrosion of its parts, and also, the liquid may be contaminated by the products of the chemical 10 reaction which takes place between the acid and the metal.

Another serious objection occurs when the apparatus is being used to charge containers with liquids containing solid particles, such as vege- 15 table soups and the like. In such cases, the hopper may be entirely emptied before replenishment occurs, since with the valve only partially open the solid particles may lodge against it and build up a barrier sufiicient to clog the passage 0 until the obstruction offered by the valve is removed by opening it wide. The hopper may then be fully replenished, or it may not, according to whether or not the valve is again clogged before it fully closes. 25

The difficulties encountered by the above described construction, and the consequent unsatisfactory operation of the filling apparatus are entirely overcome in apparatus embodying my invention, wherein I dispense with the valve 30 in the supply pipe and substitute therefor a valve which is wholly exterior of said pipe and which has no relatively moving parts to invite sticking or clogging. The valve constructed in accordance with my invention consists of a hol- 35 low, expansible capsule, or the like, placed adjacent the discharge orifice of the supply pipe, and having its interior connected with a suitable source of compressed air, whereby it may be inflated and thus caused to expand and close 40 the discharge orifice. The valve may be made of rubber or other non-corrosive material so that it will not be affected by acids, and being entirely exterior to the supply pipe, it is readily accessible for inspection or cleaning and cannot 5 clog.

The supply of compressed air is regulated by a float-controlled valve, which is so located that the material in the hopper cannot come into contact therewith, and it is, therefore, not subje'ct to clogging, sticking, or corrosion. This valve has an extremely short stroke, so that a very small variation of position of the float will cause it to open or close. By such construction, I am enabled to maintain the level of 5 liquid in the hopper within very close limits, regardless of its character.

It is, therefore, a principal object of my invention to provide a valve structure for supply pipes which shall be wholly exterior thereto and which shall not be subject to clogging, sticking, or corrosion.

Another object is to construct a valve for the purpose described, which shall have no relatively moving parts whereby frictional losses are eliminated, dis-assembly for cleaning is unnecessary, clogging is prevented, and efficient and certain operation is assured at all times and under all conditions. a

A further object is to'provide in a filling apparatus, a pneumatically controlled valve which shall be readily accessible for inspection or cleaning and which shall operate to maintain a substantially constant level of liquid therein, regardless of its character.

Another object is to provide a valve which shall be of simple construction, easily actuated, efficient in operation and cheaply manufactured.

Other objects and advantages will become apparent as the description proceeds, in connection with the accompanying drawing, in which:

Fig. 1 is a sectional view through the hopper of a filling apparatus, showing a preferred form of my device installed therein.

Fig. 2 is a side elevation of the air valve drawn to a larger scale and showing certain details in section.

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2. v

Fig. 4 is a sectional view taken along the line 44 of Fig. 1.

Fig. 5 is an enlarged view of a portion of the parts illustrated in Fig. 1.

The structural details of the filling apparatus are well known in the art and form no part of the present invention and, therefore, I have shown only so much of it as is necessary to a proper understanding of the apparatus embodying the invention. The hopper l rotates around the inclined shaft 2 and is adapted to contain a quantity of liquid material 3 which is to be discharged therefrom in small quantities into the containers to be filled. I have not shown the mechanism for transferring the material from the hopper to the containers since, as above pointed out, such mechanism forms no part of my invention, and is unnecessary to an understanding thereof, but it will be understood that the apparatus illustrated is provided with suitable means for-this purpose.

.-The supply pipe 4 is received in a bore provided in the upper end of the U-shaped bracket 5 and is rigidly secured thereto by the locknuts 6, co-operating with the threaded portion I. A manually operated valve 8 may be provided in the supply pipe 4 for cutting oif the supply of liquid when the apparatus is not in use.

The bracket 5 is adjustably mounted upon the inclined shaft 2 and into the upwardly turned end of its lower arm 9 is screwed the connector I8 which forms a support for the expansible capsule II. The lower arm of the bracket is provided with the passage I2 which communicates with the interior of the capsule I I, through an airtight connection provided by an annular groove in the capsule i co-operating with a corresponding tongue l3 provided upon the underneath side of. the collar I4 formed on the end of the connector ID. The nut and washer I5 serve to insure a tight fit of the parts.

The capsule II, which may be formed of rubber or other non-corrosive material, is spheroidal in shape in order to reduce splashing and carries the yieldable rubber stopper I6 which is adapted to co-operate with the chamferred discharge orifice Il. It will be seen that upon the admission of compressed air to the interior of the capsule, it will be distended, and in so doing will carry the stopper I6 upwardly and forcibly insert it into the discharge orifice of the supply pipe, thus interrupting the flow of liquid therefrom. This condition will obtain until the pressure in the capsule is relieved, whereupon the capsule will contract so as to withdraw the stopper and allow the flow of liquid to be resumed.

Compressed air is supplied to the interior of the capsule through the passage I2, which is connected with the air pipe I8. The pipe I8 leads from the passage IS in the block 20 which is secured to a boss formed upon the rear side of the bearing 2|.

Referring to Figs. 2 and 3, the valve housing 22 is mounted upon the block 20 by means of suitable screws, passing through holes 23. The housing 22 is provided with a central vertical bore 24, which is counterbored as at 25, in order to receive the threaded plug 26. The plug 26 is also centrally bored as at 21, and is provided with a circumferential groove 28 which communicates withthe bore 21 by means of the passage 29. A valve 30 is adapted to seat upon the inner end of the block 26, and may be held in position by the pin 3|. When the pin is in its lowest position, the valve 30 opens by the force of gravity and the pressure of the compressed air upon its top face.

The block 20 is provided with a passage 32 to one end of which is connected the pipe 33 which leads from any suitable source of compressed air. The other end of the passage 32 communicates with the passage 34 in the valve housing 22 which is adapted to register with the annular groove 28 in the plug 26. A passage 35 connects the chamber 24 with the passage I9.

As will be seen from an inspection of Fig. 2, the chamber 24 is also provided with an escape passage 36, which is controlled by the needle valve 31 which may be screwed in or out in order to vary the effective size of the passage. The

needle valve 37 is cut away as at 38 to allow the escape of air and the locknut 39 is provided to lock the valve in any desired position.

A pair of arms 40 carry the adjustable tappet 4| which is adapted to co-operate with the pin 3|. The arms 4|] are supported by the bolts 42, screwed into the bearing 2|, and are interconnected by means of the semi-circular member 43. A float 44, resting upon the surface of the liquid 3 is provided with the rod 45 which is attached to the member 43, so that movement of the float will be communicated to the tappet 4|. A stop member 46 is secured to the arm 41 and passes around the rod 45 in order to prevent the fioat from dragging on the bottom of the hopper, in the event the liquid supply is cut off.

The operation of the device will be apparent, from the foregoing description. When the level of liquid in the hopper is at a maximum the float 44 lowers the tappet 4| so that the valve 30 is opened by the pressure of the air in the bore 27, whereupon the air pressure is communicated to the interior of the capsule I. The capsule II is then maintained'in a distended position so that the stopper I6 is seated against the discharge orifice l1, and the supply of liquid is cut off. If, under these conditions, some of the material is discharged from the hopper, the level will fall and with it the float 44. The tappet M is thus elevated so as to close the valve 30. As above pointed out, the length of stroke of the valve 3!! is extremely short so that a very slight fall of the level of the liquid in the hopper I will cause it to be closed, whereupon the chamber 26 is cut oii from communication with the bore 21. The air confined under pressure in the chamber 24 and capsule l l, thereupon escapes to the atmosphere through the escape passage 36, thus relieving the pressure, whereupon the capsule contracts and aided by the pressure of material in the supply pipe 4, withdraws the stopper l6, whereupon the liquid discharges into the hopper.

The level in the hopper now rises, lifting the float 44 which allows the valve 30 to open simultaneously. As the valve opens, the supply of compressed air to the chamber 24 increases to a point where the escape passage 36 cannot relieve the pressure fast enough, whereupon the capsule expands and seats the stopper against the discharge orifice, cutting off the supply of liquid therethrough. The cycle of operations is then repeated as long as liquid is discharged from the hopper.

It will be seen that I am enabled to maintain the level of liquid in the hopper within very close limits by reason of the extremely small strokeof the air valve. The operation of the capsule may be regulated by varying the settings of the needle valve 31 or the tappet Al. The bearing 2| may also be adjusted to suit conditions.

It will also be noted that the valve II is not subject to clogging or corrosion, has no moving parts to invite sticking, or jamming, and being wholly exterior to the supply pipe, it is readily accessible for inspection or cleaning.

While for purposes of illustration I have illustrated only one specific embodiment of my invention, I wish to be understood that many changes and modifications may be made therein without departing from the spirit of said invention and I regard myself as entitled to all such changes and modifications as fall within the scope of the claims hereto appended.

Having thus described my invention and in what manner the same may be used, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for maintaining a constant level of liquid in a reservoir comprising a support, a bracket mounted for vertical adjustment on said support and having a U-shaped extension thereon, a liquid supply pipe for discharging liquid into a reservoir and having its discharge end secured to one extremity of the U- shaped extension, an expansible capsule mounted opposite the discharge end of said pipe on the other extremity of said U-shaped extension and adapted to open and close the discharge end of said supply pipe, a supply passage extending through a portion of said bracket and communicating with the interior of said capsule, a valve housing secured to said bracket and having a valve therein, a conduit connecting the valve housing with said passage, and a fioat pivotally secured to said bracket and adapted to actuate the valve in accordance with the level of liquid in the reservoir.

2. A liquid supply mechanism, comprising a bracket having a U-shaped extension thereon, a liquid supply pipe secured adjacent its discharge end to one extremity of said U-shaped extension, an expansible capsule mounted opposite the dis- 5 charge end of said pipe on the other extremity of said U-shaped extension and adapted to open and close the discharge end of said supply pipe,

a supply passage extending through a portion of said bracket and communicating with the interior of said capsule, a valve housing secured to said bracket and having a valve therein, a conduit connecting the valve housing with said passage, and. means for actuating said valve.

3. An apparatus for maintaining a constant level of liquid in a reservoir, comprising a shaft projecting into said reservoir, a bracket mounted on said shaft having a U-shaped extension thereon, a liquid supply pipe having its discharge end secured to one extremity of the U- shaped extension, an expansible capsule mounted on the other extremity of said U-shaped extension and adapted to open and close the discharge end of said supply pipe, a conduit extending from said bracket to said U-shaped extension for supplying a pressure to said capsule, a valve in said conduit, and a means connected with said valve for actuation by the liquid in said reservoir whereby the supply of pressure to the capsule is regulated by the level of the liquid in said reservoir.

4. An apparatus for maintaining a constant level of liquid in a reservoir, a liquid supply pipe having a discharge orifice for the discharge of liquid into a reservoir, a closure memher for said discharge orifice disposed exteriorly of said pipe, a common support for holding said supply pipe and said closure member in operative relation, and pneumatic control means integral with said support and actuated by the level of the liquid in said reservoir for operating said closure member to open and close said discharge orifice in accordance with the level of liquid in such reservoir, and a conduit associated with said support and connecting said pneumatic control means with said closure member.

5. An apparatus for maintaining a constant level of liquid in a reservoir, a liquid supply pipe having a discharge orifice for the discharge of liquid into a reservoir, an expansible capsuleg adjacent the discharge orifice, a support and extension thereof for holding said supply pipe and said expansible capsule in operative relation,

a conduit integral with said support for supplying a pressure to said capsule to expand the same and close said discharge orifice, a valve in said conduit, a means operatively associated with said valve whereby the supply of pressure to the capsule is regulated by the level of liquid in such reservoir, and means for relieving the pressure in the capsule when said valve is closed.

6. An apparatus for maintaining a constant level or" liquid in a reservoir, comprising a liquid supply pipe having a discharge orifice for the discharge of liquid into a reservoir, and expan- 5 sible means exterior of said pipe and opposite the discharge orifice, a support carrying said supply pipe and expansible means, and having a conduit connecting said expansible means with float controlled means for admitting air under pressure into said expansible means when the liquid level in such reservoir is normal to expand the same and close said orifice whereby discharge of liquid therefrom is prevented, and means for allowing the escape of said air from said expansible means when the level of liquid in such reservoir falls below normal.

7. In an apparatus for maintaining a constant level of liquid in a supply reservoir comprising a liquid supply pipe having a discharge orifice for the discharge of liquid into areservoir, and an expansible closure member for said discharge orifice disposed exteriorly of said pipe, a float, a support carrying said supply pipe and said expansible means and having a conduit connecting said expansible means with pneumatic means controlled by said float for actuating the closure member to open and close said discharge orifice in accordance with the level of liquid in such v reservoir.

8. An apparatus for controlling a flow of liquid being operated by an accumulation of liquid 10 flowing from said pipe to admit pressure to said expansible closure member to close said discharge orifice or to release pressure from said expansible closure member to open said discharge orifice. v

KAARE OMSTED. 

